Linux 6.1 compat: open inside tmpfile()

commit d27c81847b upstream

Linux 863f144 modified the .tmpfile interface to pass a struct file,
rather than a struct dentry, and expect the tmpfile implementation to
open inside of tmpfile().

This patch implements a configuration test that checks for this new API
and appropriately sets a HAVE_TMPFILE_DENTRY flag that tracks this old
API.  Contingent on this flag, the appropriate API is implemented.

Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Antonio Russo <aerusso@aerusso.net>
Closes #14301
Closes #14343

module/os/linux/zfs/zpl_inode.c

@@ -224,12 +224,17 @@ zpl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
 
 #ifdef HAVE_TMPFILE
 static int
+#ifndef HAVE_TMPFILE_DENTRY
+zpl_tmpfile(struct user_namespace *userns, struct inode *dir,
+    struct file *file, umode_t mode)
+#else
 #ifdef HAVE_TMPFILE_USERNS
 zpl_tmpfile(struct user_namespace *userns, struct inode *dir,
     struct dentry *dentry, umode_t mode)
 #else
 zpl_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
 #endif
+#endif
 {
 	cred_t *cr = CRED();
 	struct inode *ip;
@@ -252,11 +257,21 @@ zpl_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
 	if (error == 0) {
 		/* d_tmpfile will do drop_nlink, so we should set it first */
 		set_nlink(ip, 1);
+#ifndef HAVE_TMPFILE_DENTRY
+		d_tmpfile(file, ip);
+
+		error = zpl_xattr_security_init(ip, dir,
+		    &file->f_path.dentry->d_name);
+#else
 		d_tmpfile(dentry, ip);
 
 		error = zpl_xattr_security_init(ip, dir, &dentry->d_name);
+#endif
 		if (error == 0)
 			error = zpl_init_acl(ip, dir);
+#ifndef HAVE_TMPFILE_DENTRY
+		error = finish_open_simple(file, error);
+#endif
 		/*
 		 * don't need to handle error here, file is already in
 		 * unlinked set.